1. Field of the Invention
The present invention relates to a method for limbing and bucking selected standing trees in a forest by means of a harvesting device moved by a skidder or a corresponding carrier. The invention also relates to the harvesting device designed to carry out the method.
2. Description of the Prior Art
There are several machines available for harvesting trees, but at the present time there is no suitable machine which can efficiently be used in selective logging.
In selective logging, we are forced to fell certain trees amidst others and to pass them through narrow spaces to the driveway. Little room is left for moving and working; therefore the dimensions of the machine constructions should be small. In addition, good movability and speed of operation presuppose light constructions which also must be aimed at in order to prevent root damages. The third important condition in striving for efficiency is the extension length; however by adapting conventional solutions, the realization of this requires a massive support carrier an thus seems to conflict with the other characteristics set forth to a harvester for selective logging.
Because the mechanization of selective logging will become ever more timely due to the increasing labour costs and decreasing supply of labour power, many attempts have been made to solve the problems mentioned above. In this connection reference can be made, for example, to U.S. Pat. No. 3,536,113. However, the developed solutions suffer from the disadvantages of high cost, complexity, and limitations in maneuverability and reliability.